The Daily Grind: What produces a visceral reaction in you?

Every RPG has giant spiders. Inevitably. Despite the fact that such creatures couldn't possibly support their own body weight and other natural physics problems, you will find them. And arachnophobes the world over will cringe, because it will usually culminate in having to dive into an entire dungeon filled with spiderwebs and chittering eight-eyed things the size of a Hummvee. Not to mention all of the quests where your character has to smash them and then rifle around in what's left of their corpse and you get the general idea. If you're not comfortable with the idea of unholy, bulbous, overlegged creatures scuttling about, these parts aren't terribly comfortable even though you know it's just a game.

Today, we ask you what produces that sort of bred-in gut reaction when you come across it? Giant bugs, blood, and slimy things are all common ones for a negative reaction, but there are others, and some of them might even be unique to your own sensibilities. So we'd like to know, what gets you at a basic level, even when you're totally aware it's just a game? (And if any developers are reading right now, bonus question: why all the spiders, guys? Come on.)